Added the inLocalTimeZone parameter to the prepareResponse function. …

…This defaults to false (existing behaviour) so is backwards compatible.

When inLocalTimeZone = false, dates are returned in the format: "endDate":"2022-12-22T16:51:30.000Z"
When inLocalTimeZone = true, dates are returned in the format: "endDate":"2022-12-22T11:51:30.000-0500"

This allows performance improvements, because you don't have to perform further date processing on the values to convert them back into the local time zone.

This PR adds the flag as a parameter to getSleepSamples. It can easily be added to other functions as required.

index.android.d.ts

@@ -181,9 +181,11 @@ declare module 'react-native-google-fit' {
     /**
      * Get the sleep sessions over a specified date range.
      * @param {Object} options getSleepData accepts an options object containing required startDate: ISO8601Timestamp and endDate: ISO8601Timestamp.
+     * @param inLocalTimeZone return start and end dates in local time zone rather than converting to UTC.
      */
     getSleepSamples: (
-      options: Partial<StartAndEndDate>
+      options: Partial<StartAndEndDate>,
+      inLocalTimeZone: boolean
     ) => Promise<SleepSampleResponse[]>
 
     saveSleep: (

index.android.js

@@ -689,17 +689,18 @@ class RNGoogleFit {
   /**
    * Get the sleep sessions over a specified date range.
    * @param {Object} options getSleepData accepts an options object containing required startDate: ISO8601Timestamp and endDate: ISO8601Timestamp.
+   * @param inLocalTimeZone return start and end dates in local time zone rather than converting to UTC
    */
 
-  getSleepSamples = async (options) => {
+  getSleepSamples = async (options, inLocalTimeZone = false) => {
     const { startDate, endDate } = prepareInput(options);
 
     const result = await googleFit.getSleepSamples(
       startDate,
       endDate
     );
 
-    return prepareResponse(result, "addedBy");
+    return prepareResponse(result, "addedBy", inLocalTimeZone);
   }
 
   saveSleep = async (options) => {

src/utils.js

@@ -48,7 +48,7 @@ export function prepareInput(options) {
   return { startDate, endDate, bucketInterval, bucketUnit };
 }
 
-export function prepareResponse(response, byKey = 'value') {
+export function prepareResponse(response, byKey = 'value', inLocalTimeZone = false) {
   return response
     .map(el => {
       if (!isNil(el[byKey])) {
@@ -57,8 +57,13 @@ export function prepareResponse(response, byKey = 'value') {
         // the Chrome V8 debugger, but not on device. Using momentJS here to get around this issue.
         // el.startDate = new Date(el.startDate).toISOString()
         // el.endDate = new Date(el.endDate).toISOString()
-        el.startDate = moment(el.startDate).toISOString()
-        el.endDate = moment(el.endDate).toISOString()
+        if (inLocalTimeZone) {
+          el.startDate = moment.parseZone(el.startDate).toISOString(true)
+          el.endDate = moment.parseZone(el.endDate).toISOString(true)
+        } else {
+          el.startDate = moment(el.startDate).toISOString()
+          el.endDate = moment(el.endDate).toISOString()
+        }
         return el
       }
     })